In some existing series or models of printers, some users use the corresponding adapter and ink cartridge of the jet printer, whose structure mainly consists of an ink chamber for accommodating the ink, an ink outlet for supplying ink to the printing head, an air inlet section, a valve structure for keeping the ink chamber stable negative pressure, a chip for sending ink cartridge information to the printer and an printer adapter for positioning the chip (as shown in FIG. 1, which shows the diagram of the existing printer adapter and ink cartridge). It works in such a manner: First, install the adapter 2 that comprises a chip 1 containing the ink information into the printer. After the adapter 2 is installed into the printer, all contacts on the chip 1 fit closely with those on the printer. Then, install the ink cartridge 5 into the adapter 2 with the ink supply needle inserted into the ink outlet of the ink cartridge 5. The printer starts working normally. After the ink is run out, the printer promotes to change the ink cartridge 5. Take out the ink cartridge 5, and change a new one. After rereading the ink information, the printer continues working.
While the printer is working, all contacts on the chip 1 and those on the printer constitute a connected circuit. The printer can detect the ink level information on the chip 1. When changing the ink cartridge, the circuit mentioned above must be disconnected. Upon detecting the circuit has been disconnected, the printer can know the change action of the ink cartridge and erase the ink level information saved on the printer, so as to obtain the ink level information of the new ink cartridge. Otherwise, if the circuit is not disconnected, the printer would not erase the stored ink level information, which would make the information not identical with that of the new ink cartridge saved on the chip. The printer will generate an error message of printing failure.
However, the problem existing in the prior art is that, if the adapter is not taken out while changing the ink cartridge, the circuit connecting the chip and the printer will keep in the connected status and can't be disconnected automatically, which would result in an error message of printing failure generated on the printer. Therefore, some series of printers now have a set of programs, which makes the chip not reset unless detached with the printer. Namely, when changing the ink cartridge, the user using the adapter must take out both the ink cartridge and the adapter to make the said circuit disconnected. After the ink cartridge is reinstalled, the replacement purpose is achieved. This increases the adapter disassembly and assembly process, reduces the service life of the adapter and increases the workload and cost of the user.